Toner for dry developing

Abstract

A toner for dry developing, containing a colorant and a binder and giving such a toner image on a transfer sheet upon fixation that has an image density I and a gross of G % when the toner deposits on the transfer sheet in an amount of M mg/cm 2 , wherein I, G and M have the following relationship: I=a·M+b where 0<a≦3 and 0≦b, G=α·M+β where 0<α<15 and 0≦β, and G.sub.AV ≧10 where G AV is an average of G when M=0.2, 0.4, 0.6, 0.8 and 1 mg/cm 2 .

What is claimed is: 
     
       1. A toner for dry developing, comprising a colorant and a binder and giving a toner image on a transfer sheet upon fixation, said toner image having a density I and a gloss of G % when said toner deposits on said transfer sheet in an amount of M mg/cm 2 , said I, G and M having the following relationship:   I=a·M+b     where 0<a≦3 and 0≦b   G=α·M+β       where 0<α<15 and0≦β, and   G.sub.AV ≧10       where G AV  is an average of G when M=0.2, 0.4, 0.6, 0.8 and 1,   wherein said binder comprises a first resin and a second resin having a glass transition point different from that of said first resin and greater by no more than 5° C. than that of said first resin,   wherein said second resin is a styrene-acrylate copolymer having a number average molecular weight Mn of 3,000-30,000, a weight average molecular weight Mw of 9,000-50,000 and a ratio of Mw/Mn of no more than 3, and   wherein the weight ratio of said first resin to said second resin is in the range of 95:5 to 60:40.   
     
     
       2. A toner as claimed in claim 1, wherein said first resin has a glass transition point of at least 55° C. 
     
     
       3. A toner as claimed in claim 2, wherein said first resin has a softening point of 100-120° C. 
     
     
       4. A toner as claimed in claim 1, and having a volume average particle diameter of 5-9 μm and such a particle size distribution of toner particles that particles having a diameter of 4 μm or less account for no more than 40% of the total number of said toner particles and particles having a diameter of at least 12 μm account for no more than 10% of the total volume of said toner particles. 
     
     
       5. A toner as claimed in claim 1, wherein said colorant is present in an amount of 3-12% by weight based on the weight of said toner and consists of carbon black and at least one additional colorant selected from the group consisting of yellow colorants, magenta colorants and cyan colorants, said additional colorant being present in an amount of 10-30% by weight based on the weight of said carbon black. 
     
     
       6. A toner as claimed in claim 1, wherein said colorant is a yellow colorant and is present in an amount of 4-10% by weight based on the weight of said toner. 
     
     
       7. A toner as claimed in claim 1, wherein said colorant is a magenta colorant and is present in an amount of 4-10% by weight based on the weight of said toner. 
     
     
       8. A toner as claimed in claim 1, wherein said colorant is a cyan colorant and is present in an amount of 1-5% by weight based on the weight of said toner. 
     
     
       9. A toner for dry developing, comprising a colorant, and a binder including a first resin and a second resin having a glass transition point different from that of said first resin and greater by no more than 5° C. than that of said first resin, wherein said first resin has a glass transition point of at least 55° C. and a softening point of 100-120° C., wherein said second resin has a number average molecular weight Mn of 3,000-30,000, a weight average molecular weight Mw of 9,000-50,000 and a ratio of Mw/Mn of no more than 3, and wherein the weight ratio of said first resin to said second resin is in the range of 95:5 to 60:40. 
     
     
       10. A toner as claimed in claim 9, wherein the first resin is a polyol resin which is either (A) a resin having (i) a main skeleton containing an epoxy resin unit and an alkylene oxide unit and (ii) inert terminal ends, or (B) a resin obtained by reacting (a) an epoxy resin, (b) an alkylene oxide addition product of a dihydric phenol compound or a glycidyl ether of the product, (c) a compound having one active hydrogen capable of reacting with the epoxy resin (a), and (d) a compound having at least two active hydrogens capable of reacting with the epoxy resin (a). 
     
     
       11. A toner as claimed in claim 9, and having a volume average particle diameter of 5-9 μm and such a particle size distribution of toner particles that particles having a diameter of 4 μm or less account for no more than 40% of the total number of said toner particles and particles having a diameter of at least 12 μm account for no more than 10% of the total volume of said toner particles. 
     
     
       12. A toner as claimed in claim 9, wherein said colorant is present in an amount of 3-12% by weight based on the weight of said toner and consists of carbon black and at least one additional colorant selected from the group consisting of yellow colorants, magenta colorants and cyan colorants, said additional colorant being present in an amount of 10-30% by weight based on the weight of said carbon black. 
     
     
       13. A toner as claimed in claim 9, wherein said colorant is a yellow colorant and is present in an amount of 4-10% by weight based on the weight of said toner. 
     
     
       14. A toner as claimed in claim 9, wherein said colorant is a magenta colorant and is present in an amount of 4-10% by weight based on the weight of said toner. 
     
     
       15. A toner as claimed in claim 9, wherein said colorant is a cyan colorant and is present in an amount of 1-5% by weight based on the weight of said toner.